A facile route for CdSe nanoparticles: synthesis and structural characterisation

Abstract

Semiconducting CdSe nanoparticles of a few nanometers in size were synthesised by solvothermal decomposition of novel, single-source molecular precursor Cd(II) complex of bis(aminoethyl)selenide ((NH2CH2CH2)2Se.CdCl2)) using quinoline as coordinating agent at 200°C. Particle size, structural phase, elemental compositions, morphology and optical bandgap of as-synthesised nanoparticles were characterised using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDAX), transmission electron microscopy (TEM) and UV–Vis spectroscopy. The XRD pattern revealed that hexagonal CdSe nanocrystallites of ≈7 nm average size can be obtained by the solvothermal decomposition of ((NH2CH2CH2)2Se.CdCl2)) in quinoline. Elemental composition ratio of Cd:Se reveals non-stochiometric phase as confirmed standard less ZAF quantification, where Z, A and F are the matrix correction parameters, describing the atomic number effect (stopping power and backscatter effect), the absorption effect, and the fluorescence effect, respectively, in EDAX. Absorption spectra show blue shift in the absorption in nano particles with respect to their bulk counterpart and the calculated optical bandgap is estimated at 3·94 eV. This method has several advantages such as non-toxic and non-pyroforic single-source precursor, relatively low temperature and avoids the need for inert environment. However, quinoline used as coordinating agent has proved ineffective in capping and dispersing the nanoparticles and need to be further investigated.